Abstract
This work aimed at exploring the genetic variability, population structure and relationships of Lathyrus sativus L. germplasm using isozyme analysis. The data of isozyme analysis revealed 12 putative polymorphic loci of a total 33 alleles, indicating that studied accessions express good allelic richness and had an apparent rate of allogamy. The mean average of the expected heterozygosity (0.483) was more than the mean average of the observed heterozygosity (0.449) suggesting an apparent rate of allogamy taking place in Lathyrus sativus L. The average of total heterozygosity (H-T) and intra-accessional genetic diversity (H-S) were 0.559 and 0.428 respectively indicating that majority of genetic diversity was intra-accessional. The low levels and non-significant of genetic diversity among accessions (D-ST = 0.190, X-2 = 62.59, p = 0.029) were probably indicative of occurrence of several gene flows. The coefficient of gene differentiation (G(ST)) showed significant variation, suggesting the heterogonous distribution of L. sativus accessions among different geographic regions. The mean average of F-ST was 0.327, suggesting the occurrence of random mating system for the studied accessions and reflecting adaptation to strong environmental dissimilarities. Cluster analysis based on isozyme data suggested that the environment had no influence on the genetic diversity and confirmed that Lathyrus sativus L. had a polyphyletic origin.